IfcPlacement

Definition from ISO/CD 10303-42:1992: A placement entity defines the local environment for the definition of a geometry item. It locates the item to be defined and, in the case of the axis placement subtypes, gives its orientation.

Additional definition from ISO/WD SC4/WG12/N071 Part42.2 geometry_schema: A placement locates a geometric item with respect to the coordinate system of its geometric context.

Definition from IAI: The IfcPlacement is an abstract supertype not to be directly instantiated, whereas the STEP P42 entity placement can be instantiated to define a placement without orientation. The derived attribute Dim has been added, see also note at IfcGeometricRepresentationItem.

NOTE: Corresponding STEP entity: placement. Please refer to ISO/IS 10303-42:1994, p. 27 for the final definition of the formal standard.

HISTORY: New entity in IFC Release 1.0

EXPRESS specification:

ENTITY IfcPlacement

ABSTRACT SUPERTYPE OF

(ONEOF(IfcAxis1Placement, IfcAxis2Placement2D, IfcAxis2Placement3D))

SUBTYPE OF (

IfcGeometricRepresentationItem);

Location

IfcCartesianPoint;

DERIVE

Dim

IfcDimensionCount := Location.Dim;

END_ENTITY;

Attribute definitions:

Location	:	The geometric position of a reference point, such as the center of a circle, of the item to be located.
Dim	:	The space dimensionality of this class, derived from the dimensionality of the location.

Inheritance graph

ENTITY IfcPlacement;

ENTITY IfcRepresentationItem;

INVERSE

LayerAssignments

SET OF IfcPresentationLayerAssignment FOR AssignedItems;

StyledByItem

SET [0:1] OF IfcStyledItem FOR Item;